1. Field of the Invention
This invention relates to the shape of a main combustion chamber formed in the top surface of a piston of a swirl chamber type diesel engine.
2. Description of the Prior Art
The so-called swirl chamber type diesel engines are popularly used, in which a swirl chamber is provided and combustion is transmitted to a main combustion chamber by shooting forth flame from the swirl chamber with a view to attaining better combustion.
In such swirl chamber type diesel engines, their main combustion chambers are designed with special shapes so that effective use is achieved of the air in the main combustion chamber formed in the top surface of a piston.
With respect to their shape, the conventional main combustion chambers can be broadly divided into the twin-leaved type main combustion chambers and the grooved type main combustion chambers. The twin-leaved type main combustion chambers are suited for medium to low-speed diesel engines; but not for high-speed ones, with which poor combustion results. In contrast, the grooved type main combustion chambers are suited for high-speed diesel engines, but unsuited for low-speed ones because of worsening combustion condition.